I mean that higher end jobs don't want to be in an area where they don't enjoy. They are the higher tax payers and they want to enjoy their lives far from the kind of people that live in rent controlled housing - there are differences in education, culture, habits that make people want to separate. Not elitism or something like this, just living with similar people. Whatever we want or say, people are different, not identical, not equal as potential friends and buddies.
Well, in Sidney, you won't live next to rent controlled housing type people. (At least, there won't be many, and you can pick a place where you don't.)
But you won't live next to people who are similar to you, either. (Though that dirt farmer's land may be worth more than your startup...)